SCHEDULE III -- SUPPLEMENTARY INSURANCE INFORMATION (Details) - Property/Casualty Insurance [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplementary Insurance Information, by Segment [Line Items]
Deferred policy acquisition costs		$ 5,608	$ 1,172	$ 1,443
Reserves for unpaid claims and claim adjustment expenses		680,274	576,330	513,596
Unearned premiums		53,085	21,694	25,291
Other policy claims and benefits payable		0	0	0
Net premium earned		328,145	276,011	263,335
Net investment income	[1]	18,095	14,483	12,498
Benefits, claims, losses and settlement expenses	[1]	247,518	186,481	155,750
Amortization of deferred policy acquisition costs		70,574	51,597	50,270
Other operating expenses	[1],[2]	14,043	8,180	13,682
Net premiums written		$ 353,389	$ 271,752	$ 254,653

[1] Allocations of certain expenses have been made to investment income, settlement expenses and other operating expenses and are based on a number of assumptions and estimates. Results among these categories would change if different methods were applied.

[2] Commission allowances relating to reinsurance ceded are offset against other operating expenses.